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μPD555 (μCOM-42 EVACHIP) - NEC
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NEC μCOM-42 EVACHIP
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Manufacturer NEC
Model Number μCOM-42 EVACHIP
Part Number μPD555
Introduction 1977 (launch)
General information
Family μCOM-42
Clock 100 kHz-200 kHz
Microarchitecture
Microarchitecture μCOM-42
Technology pMOS
Word size 4 bit
0.5 octets
1 nibbles
Electrical
Op. Temp -10 °C – 70 °C
Supply VDD -10 V
Supply VSS 0 V
Memory
RAM 48 B
4.8e-5 MB
0.048 kB
384 b
4.8e-8 GB
(96x4 bit)
Max Addressable Memory 2.4 kB
Stack 4 levels
Pins
Pins 64
IRQ lines 2
I/O ports 1
Input ports 1
Output ports 12
Packaging
Package DIP64 (DIP), CerDIP64 (CerDIP)

The μPD555 or μCOM-42 EVACHIP is a 4-bit evaluation/development microcontroller used for both software and hardware debugging of the μPD548 microcontroller.

The 555 is functionally identical to the μPD548 without the internal memory, which instead is needed to be supplied externally and connected via the additional pins. This chip also has a HOLD operation that allows step-by-step inspection of operations.

Design[edit]

New text document.svg This section is empty; you can help add the missing info by editing this page.

Instruction Set[edit]

Main article: μCOM-42 ISA
New text document.svg This section is empty; you can help add the missing info by editing this page.

Documents[edit]

See also[edit]

familyμCOM-42 +
first launched1977 +
full page namenec/μcom-42/μpd555 +
instance ofmicrocontroller +
manufacturerNEC +
max operating temperature70 °C +
microarchitectureμCOM-42 +
min operating temperature-10 °C +
model numberμCOM-42 EVACHIP +
nameNEC μCOM-42 EVACHIP +
packageDIP64 + and CerDIP64 +
part numberμPD555 +
pin count64 +
ram4.8e-5 MB (0.048 kB, 48 B, 384 b, 4.8e-8 GB) +
ram breakdown96x4 bit +
technologypMOS +
word size4 bit (0.5 octets, 1 nibbles) +